As a heating cooker for cooking food which is an object to be heated by heating using microwaves or the like, there has been known a heating cooker which heats food in the cavity using steam generated by a steam generator disposed outside the cavity (refer to PTL 1, for example).
Such a steam generator includes a water supply device for supplying water into the steam generator, and a drainage device for draining water in the steam generator. For example, there has been disclosed a drainage device where the drainage is performed by making use of the siphon phenomenon which is generated due to a level difference between a drainage pipe inlet and a drainage pipe outlet (hereinafter referred to as drainage by siphoning) (refer to PTL 2, for example).